Currently mute LED and micmute LED share the same GPIO polarity.

So split the polarity for mute and micmute, in case they have different
polarities.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20200430083255.5093-1-kai.heng.feng@canonical.comSigned-off-by: Takashi Iwai <tiwai@suse.de>